Speedometer Adjustment
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Joined: Oct 2013
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Speedometer Adjustment
I'm driving my project pickup 1978 3/4 ton 2wd that I put on a 1979 3/4 ton 4wd frame and running gear. Both have 4.10 gears, 2wd had 31x10.5x16.5 tires and the 4wd has 235/85/16, both have c6 trannys but my speedometer is off about 10 mph at 60 (it reads 70) do I need a new gear on my speedometer cable since it's a 4wd now? I wouldn't think so but not sure...I'm using the 2wd speedometer cable and gear on the 4wd tranny. Ideas? Thanks.
Laughing Gas
Joined: Sep 2003
Posts: 968
Likes: 5
From: Corbett, Oregon
You will need to change out the gear on the speedometer cable, the one that slips into the transmission, or transfer case.
Since the speedo is reading too fast you will need to install a gear with more teeth. I would start with a gear with two more teeth than your current gear.
Be aware there are left handed and right handed gears. Be sure your replacement gear is the same cut as the original.
Good luck.
Since the speedo is reading too fast you will need to install a gear with more teeth. I would start with a gear with two more teeth than your current gear.
Be aware there are left handed and right handed gears. Be sure your replacement gear is the same cut as the original.
Good luck.
Postmaster
Joined: Oct 2010
Posts: 4,656
Likes: 4
From: Northern and Southern Cal
For your shopping pleasure.
Ford stuff is down the page a bit.
Speedometer Gear, Speedometer Gears, Ford, GM, Dodge 700R4
Ford stuff is down the page a bit.
Speedometer Gear, Speedometer Gears, Ford, GM, Dodge 700R4
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